SERUM-LIPOPROTEINS AND LIPASE ACTIVITIES IN PRIMARY BILIARY-CIRRHOSIS

Previous studies have demonstrated increased high density lipoprotein2 (HDL2) cholesterol concentration in patients with primary biliary cirrhosis (PBC), but the underlying mechanism is unclear. We have studied the possible pathogenic role of derangement in lipoprotein lipase (LPL) and hepatic lipase (HL) activities by parallel measurements of these enzyme activities and serum lipoprotein concentrations in 13 PBC patients, who on the whole had only slight or no clinical symptoms. Total HDL cholesterol levels were increased. The mean HDL2 cholesterol concentration was 1.49 +/- 0.75 mmol/l (s.d.) and the mean HDL3 cholesterol concentration 0.55 +/- 24 mmol/l, indicating an increased HDL2/HDL3 cholesterol ratio. Both LPL and HL activities were markedly decreased. The extremely low LPL activities in six patients could be explained by the presence of an LPL inhibitor in plasma; in the remaining seven patients where LPL activities were also subnormal, however, this was not the case. In contrast to other reports, we could not demonstrate an HL inhibitor that explained the low HL activities. Our data suggest that the HDL subfraction alterations in PBC can be explained by a decreased HL activity, but that other mechanisms may also affect lipoprotein metabolism at this early stage of the disease.